Concrete slabs have been manufactured over the past years using a variety of forms and materials. The Romans first used a slab composition composed of quick lime, pozzolana and a kind of pumice which is now known as Roman Concrete and this freed the Romans from the use of brick and stone in building structures. This substance was subjected to change and improvement until we have what is now known as modern concrete which is composed of Portland Cement (a powder) and a variety of aggregates to fill a variety of needs.
One question has always been with us, and that is “how do we increase the tensile strength of the cured concrete?” The present answer is the use of specially made steel rods (rebars) embedded in the concrete as it cured and this gives the necessary tensile strength to the cured concrete. It is known to use other materials such as fibres, steel shavings and materials such as horse hair which when added to the concrete mix improve its tensile strength.
Now that a satisfactory additive material has been found, what sort of a container (form) can be used hold the curing mixture as it sets? The form used by early practitioners and still is in use to day is wood. Here the pieces of wood are somehow joined to-gether at their ends to form an outer boundary which is supported by a system of stakes which are driven into the lower supporting surface (generally the earth) so as to maintain a desirable shape for the curing concrete. The lower surface which supports the concrete slab must be suitably prepared ahead of time. Uncured concrete is heavy and it is not unusual to have additional stakes driven into the supporting media beneath the concrete slab at angles which are required to buttress the form in areas where it is misshapen and bent out of the desired shape so that it requires additional support. The concrete is held in this form until sufficient time has elapsed that it is cured sufficiently to allow the removal of the wooden forms.
This invention seeks to provide a form that is much easier to use, in that it is easier to set up, and yet does not impede the curing process of the concrete. It will be found that this form is easy to assemble by unskilled labour which contributes to its overall efficiency. Because this invention utilizes a metal form, means are incorporated for accurately locating the members composing this form.